Carol Klein takes the fear out of root cu ings
Winter months are the prime time to take them, so give it a go!
It’s December, surely it’s too late to think about propagation, hadn’t we better leave it until next year? But this is just the beginning of the best time to take root cuttings. Although you can take root cuttings at almost any time of year, the optimum time is November through to March.
Traditionally roots would have been gathered together and stored in damp sand until February – the quietest time of the gardening year when gardeners would have got to work to make new plants. Purportedly root cuttings take best during winter, though in my limited experience it doesn’t seem to make much difference.
Most of us accept that you can persuade a stem to take root. Stem cuttings are straightforward and many amateur gardeners will have a go, but feel out of their depth when it comes to dealing with roots. Is it because we don’t see the roots, even though they’re one of the most essential components of almost every plant? Without them plants couldn't exist.
The very first time I took some root cuttings, maybe 40 years ago, it was an experiment and one I thought was unlikely to succeed. Stumpy pieces of root from one of my favourite Oriental poppies, ‘Patty’s Plum’, were pushed down into compost until their tops were flush with the level of the soil. After just a few weeks there was a barely perceptible glimmer of green around the edge of the root
– and a couple of weeks later, much to my amazement, proper leaves started to form.
And yet we don’t need to look very far to see how straightforward this method is. Any of us who’ve tried to move an Oriental poppy, an acanthus or a Japanese anemone will know that it’s almost impossible to eradicate them and all we need do when propagating such plants is to emulate nature. The poppy, the acanthus and the anemone illustrate how these techniques for taking root cuttings emulate what nature does. With the poppy, sections of root are grown on vertically while with the anemone they’re grown horizontally, in both cases just as they grow in the ground.
Sometimes we’ll go out and dig down beside a plant to chop off a chunk of root rather than lift the whole plant or, if we have a well-rooted plant in a pot, we can knock it out and sever one or two of the thickest, newest roots. It’s important to keep roots the right way round – the top is the end closest to the crown of the plant.
The roots are cut into sections about 4-5cm (1½-2in) long and lined up so we always know which end is up – polarity is vitally important. There’s no need to make sloping cuts at the base if you keep your cuttings lined up, it just complicates matters. If you can give each one its own space so much the better. In separate modules or even little pots filled with any free-draining compost (I add plenty of grit and extra sterilised loam to my usual mix), push in the sections of root until they’re flush with the top of the compost. Cover with grit, water well.
Obviously, with horizontal cuttings there’s no right or wrong end and these are laid flat on the surface of the compost and weighted down with grit. In both cases resist the temptation to pot up until roots are made – green shoots emerge first.
'Many amateur gardeners feel out of their depth when it comes to dealing with roots'